One of the primary functions of an emergency vehicle's signaling system is to draw the attention of motorists and pedestrians to the emergency vehicle. Accomplishing this function provides safety to the driver of the emergency vehicle and approaching motorists and pedestrians. The installation and coordination of the electronic visual and audible signaling devices is typically a resource-intensive process in terms of labor and materials. Each signaling module, such as needed for the control of a lightbar, perimeter lights, siren, headlight flashers, etc. must be hand-wired and then programmed with configurations, flash patterns, and priorities.
Integrated wiring harnesses and control systems have been used for emergency vehicle signaling. Some examples of these types of control systems are disclosed in U.S. Pat. Nos. 5,422,623, 5,703,411, and 5,736,925 functional warning units
Bader et al. U.S. Pat. No. 5,422,623 discloses an emergency signaling system for a vehicle that includes one or more signaling devices such as an emergency light located on a lightbar and a housing to enclose a first control unit necessary for delivering power to the signaling device. A second control unit remote from the first is electrically coupled to the electronics in the housing and stores and controls the signal patterns for the signaling devices. The control units are connected via a bus. Separate cabling from a battery carries power and reference ground wires to each of the control units.
Bella et al. U.S. Pat. No. 5,703,411 discloses a wiring harness and control system for emergency vehicle functional warning units directed at easy and quick installation into emergency vehicles. A control unit, mounted on the underside of the rear deck of the vehicle, couples to a user-controlled console. Branches of a wiring harness connected to the control unit are routed to the lightbar, the headlights, warning lights and grille light. The control unit contains a load shedder circuit that distributes fused power to the lighting system elements.
Dawson et al. U.S. Pat. No. 5,736,925 discloses a modular lighting control system for vehicle lighting control directed at an emergency vehicle such as an ambulance. A central processor processes commands from a user-controlled interface to route power to each of the signaling devices under the control of the central processor. The signaling devices are modular in that they may be selectively coupled to the central processor for a custom installation where the selective coupling requires a wiring harness to connect each signaling device to the central processor.